[A case of fetal sacro-coccygeal teratoma]

Here is described a case of sacro-coccygeal teratoma observed in a 26th week still-born fetus characterized by differentiating aspects of the three embryonal layers with immature features of the ectodermal and mesodermal derivatives but not those of the entoderm. On the base of the findings observed, the classifying approach of these neoplasms has been reconsidered.